cerebral blood flow

Question 1

what is a stroke/CVA (cerebrovascular accident)

Answer 1

rapidly developing focal disturbance of brain function of presumed vascular origin and of >24 hrs duration

Question 2

2 causes and relative prevalence of strokes

Answer 2

infarction/blockage (85%), haemorrhage/bleed (15%)

Question 3

define transient ischaemic attack (TIA); give cause and significance

Answer 3

rapidly developing focal disturbance of brain function of presumed vascular origin that resolves completely within 24 hours; caused by temporary blockage of blood supply that is broken down quickly, so is a warning sign as indicative of big risk of stroke

Question 4

define infarction

Answer 4

degenerative changes which occur in tissue following occlusion of an artery, losing all blood supply, causing loss of all e.g. O2, glucose, nutrients etc.

Question 5

define cerebral ischaemia

Answer 5

lack of sufficient blood supply to nervous tissue resulting in permanent damage if blood flow is not restored quickly (lack of O2, nutrients, glucose etc.)

Question 6

what are hypoxia/anoxia

Answer 6

relating to just oxygen

Question 7

2 causes of occlusions

Answer 7

thrombosis, embolism

Question 8

define thrombosis

Answer 8

formation of blood clot (thrombus)

Question 9

define embolism

Answer 9

plugging of a small vessel by material carried from larger vessel e.g. thrombi from heart or atherosclerotic debris from internal carotid

Question 10

what does yellowing on vessel wall indicate, particularly at bifurcations

Answer 10

atheroclerosis

Question 11

what does loss of differentiation of colour in brain (grey matter vs white matter) indicate

Answer 11

infarction (blockage)

Question 12

epidemiology of stroke

Answer 12

3rd commonest cause of death; 100,000 deaths in UK per annum; 50% of survivors are permanently disabled; 70% show an obvious neurological deficit

Question 13

5 main risk factors for stroke

Answer 13

age, hypertension (esp. haemorrhagic stroke), cardiac disease, smoking, diabetes mellitus

Question 14

perfusion fields of main cerebral arteries

Answer 14

anterior cerebral artery: long strip from frontal lobe to pariet occipital sulcus (motor cortex supplying lower limb); middle cerebral artery: lateral section of brain (supplying trunk, head and abdomen); posterior cerebral artery: occipital lobe and inferior part of temporal lobe

Question 15

outcomes of stroke in anterior cerebral artery

Answer 15

paralysis of contralateral leg (more so than arm) and, face; disturbance of intellect, executive function and judgement (abulia); loss of appropriate social behaviour

Question 16

outcomes of stroke in middle cerebral artery

Answer 16

“classic stroke”; contralateral hemiplegia (paralysis in one side) in arm (more so than leg); contralateral hemisensory deficits (altered sensation down one side; postcentral girus); heminaopia (blindness over half the field of vision); aphasia (L sided lesion; impairment of language)

Question 17

outcomes of stroke in posterior cerebral artery

Answer 17

visual deficits: homonymous hemianopia (hemianopic visual field loss on the same side of both eyes), visual agnosia (object and face recognition)

Question 18

what are lacunar infarcts

Answer 18

small strokes happening throughout life (small bleeds) in lacune (small cavity), so appear in deep structures as a result of a small vessel occlusion

Question 19

what is a lunar infarct deficit dependent on

Answer 19

anatomical location

Question 20

risk factor of lunar infarct

Answer 20

hypertension